Press



R. G. LE TOURNEAU March 6, 1962 PRESS 5 Sheets-Sheet .2

Filed Oct. 18. 1957 Fig. '5 8/ mofar c072 fro //er March 6, 1962 R. c;. LE TOURNEAU 3,023,799

PRESS Filed Oct. 18. 1957 3 Sheets-Shet s BY 4%. T. fl W United States Patent 3,023,799 PRESS Robert G. LeTourneau, P.0. Box 2307, Longview, Tex. Filed Oct. 18, 1957, Ser. No. 691,008 4 Claims. (Cl. 153-48) My invention relates to presses, and more particularly to large size metal forming presses.

Large size metal forming presses of the prior art of which I am aware, and which are capable of exerting the required force, are unduly complex, with resulting high initial cost, as well as high maintenance costs.

The general object of my invention is to provide an improved metal forming press.

Another object of my invention is to provide an improved metal forming press which is characterized by structural simplicity.

Another object of my invention is to provide a press which can be made large and yet economical and not complex.

These and other objects are effected by my invention as will be apparent from the following description taken in accordance with the accompanying drawing, forming a part of this application, in which:

FIG. 1 is a schematic perspective view of a press in accordance with a preferred embodiment of the invention;

FIG. 2 is a plan view of the press of FIG. 1;

FIG. 3 is a schematic side elevational view, partially in phantom, of a press drive unit;

FIG. 4 is a schematic view, partly in section, lines 4-4 of FIG. 3; and

FIG. 5 is a schematic block diagram illustrating an electric control system for the press.

The press shown by FIG. 1 comprises a bed 11, a pair of drive units 13, 15, a fixed die element 17, a movable die element 19, a movable support structure 21, a pair of ram units 23, 25, and a plurality of synchronizer links 27. In the embodiment shown, the dies 17, 19 are suitably shaped for forming steel plate sheets into curved plate sections. The fixed and movable die elements 17, 19 as shown in FIG. 1, are actually integral parts of the bed 11 and the movable die support structure 21, respectively. It is understood that alternatively, the die elements can be made as separate structures and means provided for removably fixing the die elements to their respective support structures. The bed 11 is a heavy metal box structure, having generally the shape of a long rectangle in horizontal cross-section. The bed 11 is provided with suitable internal reinforcing structure (not shown), to give it the necessary strength and rigidity. The movable die support structure 21 has the same horizontal cross section shape as the bed, and is also provided with a suitable internal reinforcing structure (not shown), to give it. the necessary strength and rigidity. Each drive unit 13, 15, includes a housing assembly 29, 31, three gear reduction assemblies 33, 35, 37, and a ram support and guide assembly. The two drive units 13, 15, are identical except of course one 13 is a left hand unit, and the other 15 is a right hand unit. For simplicity, only one drive unit will be described in detail herein. The showings in FIGS. 3 and fare of the right hand drive unit 15. Each housing assembly 29, 31 is made up of a plurality of heavy steel plate members arranged to form walls and partitions which are integrally joined by welding. Each housing unit may be considered as being made up of two portions. The first portion 39 is basically a column substantially rectangular in horizontal cross-section, which extends down to the level of the bed bottom. The second portion 41 is a box structure of substantially rectangular horizontal cross-section which is supported by the first portion 39 and extends forwardly out over and above the taken at ice bed 11. The first housing portion 39 comprises an outside wall 43, an inside wall 45, a rear wall 47, and a front wall 49, and the second housing portion 41 has an outside wall 51, an inside wall 53, and a front wall 55. The inside wall 45 of the first housing portion 39 is integral and coplanar with the inside wall 53 of the second housing portion 41. The first housing portion has a longitudinal partition 57 spaced from and parallel to the out side wall 43 and extending from the rear wall 47 to the front wall 49. The front wall 49 of the first housing portion 39 extends all the way between the outside and inside walls 43, 45 up to the level of the bottom of the second housing portion 41, and then it extends only from the outside wall 43 to the longitudinal partition 57. The first housingportion 39 is provided with a transverse partition 59 extending from the inside wall 45 to the longitudinal partition 57 at a short distance rearwardly of the front wall 49. All of the walls and partitions abovementioned are made of heavy steel plate material and are integrally joined by welding. Additional bracing members (not shown) may be used as necessary, to lend the drive unit housings additional strength and rigidity. The inside rear portion of the first housing portion 39 is provided with three rectangular cavities for receiving primary gear boxes 61, as will be hereinafter more fully explained. The upper cavity extends to the top of the first housing portion 39, and the other two are located below the upper one at spaced intervals. The top of each cavity defines the upper extent of a respective gear reduction assembly 33, 35, 37. Each cavity extends from the inside wall 45 to the longitudinal partition 57. Each cavity is walled on all sides except the sides corresponding to the rear wall and the inside wall of the first housing portion 39, except that the upper cavity is not walled on its top side. The outside and inside walls 51, 53 of the second housing portion 41 are provided with rectangular forward extensions 63, at the upper and lower ends, for a purpose to be hereinafter explained. These extensions 63, 65 are bridged at top and bottom by rectangular plates 66 for additional rigidity. The first housing portions 39 are disposed symmetrically on the rear side of the bed 11 and spaced inwardly from the ends of the bed and so that a plane parallel to the housing side walls 43, 45 is perpendicular to the bed longitudinal axis. Each first housing portion 39 is fixed rigidly at its lower end portion to the bed 11.

Each gear reduction assembly 33, 35, 37 comprises a primary gear box 61 having an input pinion (not shown) and an output pinion 67, a first bull gear 69 fixed to a first shaft 71 and driving a first output pinion 73, a second bull gear 75 fixed to a second shaft 77 and driving a second output pinion 79. Each primary gear box 61 is a self-contained unit which is welded in place in a respective cavity. The primary gear box input pinion (not shown) is in each case driven by an electric motor 81 which is bolted onto the respective gear box 61. The output pinion 67 of a respective primary gear box 61 engages a respective first bull gear 69. The shaft 71 ofa respecf tive first bull gear 69 is journalled on bearings 83 which are mounted in a hub 85, the hub extending between and supported by the inside wall 45 and the longitudinal partition 57 of the first housing portion 39. Thus, the primary gear box output pinion 67 and the first bull gear 69 are housed by the outside wall 43, portions of the front and rear walls 49, 47 of the first housing portion 39 and the longitudinal partition 57. The first output pinion 73 engages the second bull gear 75. The shaft 77 of the second bull gear 75 is journalled on bearings 87, 89, one set 87 of which are mounted on the respective hub 91 which extends through and is supported by the inside wall 45 of the second housing portion 41, and another set 89 of which are mounted in a hub 93 which is fixed to the inner side of the outside wall 51 of the second housing portion 41. Thus, the first output pinion 73 and the second bull gear 75 are disposed on the outside of the housing inside walls-45, 53, and the second output pinion 7-9 is housed by the side and front walls 51, 53,55 of the second housing portion 41,a portion of the front wall 49 f the first housing portion 39, and the transverse partition 59. 7

Each of the two ram units 23, 25 aforementioned, comprises a rack 95 having teeth 97, side faces 99, and a front face 101; a rack guide 103; and a pair of rack support members 105. The rack guide 103 in each case is a rectangular heavy steel slab having parallel front and rear faces 107, 109. The rack support members 105 are rectangular lengths of heavy steel plate material. The rack 95 is disposed so that a .plane bisecting it and perpendicular to its teeth 97 also bisects the rack guide 103 along its longitudinal dimension, and is perpendicular to the front and rear faces 107, 109 of the guide. The rack 95 is spaced rearwardly from the rear face 109 of the .guide 103. A rack support member 105 is welded along one longitudinal edge to a rack side face 99 adjacent the rack rear face 101, and is welded along the other longitudinal edge to the rear face 109 -of the rack guide 103 along a line parallel to and inwardly spaced from a respective longitudinal edge of the rack guide. Thus, in horizontal cross section, a truncated isosceles triangle is formed with the guide 103 as its base, the rack support members 105 as sides, and .the rack front face 101 as top. The portions of the rack guide which extend outwardly beyond the rack support member-rack guide joints serve as guide bearing surfaces, as will be hereinafter explained. Each ram unit 23, 25 is rigidly fixed at its lower end to the top of the movable die support structure '21 and is disposed perpendicular thereto, with the front and rear face's l07, 109 of the rack guide 103 parallel to themutuallyparal'lel axes-of the first and second shafts 71, .77 of the gear reduction assemblies 33, 35, 37.

A set ofrack guide rollers 111 is mounted,-one at the upper end portion and one at the lower end portion, of the frontwall 55 of the second housing portion-41. Each set comprises four rollers 11-1, with one pair engag ng the front rack guide bearing surfaces and the other pair engaging the rear rack .guide bearing surfaces. The first pair will be herein referred to as from rollers and the second pair as rear rollers. The front rollers are disposed just inside the-extensions 63, 65 of the second housing portion side walls 51, 53 and are journalled on shafts which are supported on said side Walls. The rear rollers are disposed just inside the second housing portion side walls 51, 53 just rearward of its front wall 55 and are journalled on shafts which are supported on said side walls. All roller shafts are mutually parallel. Pairs of rollers are coaxial, and the axes of respective sets of rollers lie in a common horizontal .plane.

I A bolt ring 113 is-fixed to each first shaft 71 of each gear reduction assembly 33, 35', 37 at its end beyond the respective first output pinion 73. A synchronizer-link in the form of a tubular shaft 115 having a bolt flange 117 at each end is bolted to the said bolt rings 113 of oppositelyfacing gear reduction assemblies. Thus, with'three gear reduction assemblies in each drive unit, there are three synchronizer links each extending from a. gear reduction-assembly of one drive unit to the corresponding gear reduction assembly of the other drive unit. Thus, all gears of the entire press are mechanically linked and so are mechanically synchronized. The gears of the gear reduction assemblies of a respective drive unit are mechanically linked through the respective rack, while the gear reduction assemblies of one drive unit are mechanically linked to those of the other by means of the synchronizer links.

Electric motors 81 are all energized simultaneously from a common power source (not shown) by means of a conventional electric controller 119, as illustrated by the schematic block diagram of FIG. 5.

In operation, a sheet of material to be formed is placed in the press, the controller is actuated to energize all motors simultaneously in the direction to cause the rams and therefore the movable die to move downward. The movable die will continue its downward movement until the motors stall, at which time the operator actuates the controller to reverse the motors, and the movable die moves upward to open the dies suificiently so that the formed sheet can be readily removed. Limit switches, not shown, are provided to limit upward movement of the rams. It is of course understood that the lower limit of ram travel can be determined in various ways other than stalling the motors, as for example, by automatic electric means responsive to motor load, strain gauges, or ram travel limit. The motors, being energized in parallel and driving gear reductions which are all mechanically synchronized, will tend to automatically distribute the load equally among themselves, thus assuring that equal forces are applied by the rains, so that the die action is uniform.

It is to be understood that any desired number of gear reduction units and electricmotors per drive unit could be used, and that any desired number of drive units could be used, it only being necessary that all gearreduction systems be mechanically linked together.

It will be apparent from the foregoing that I have provided a press which can be made in large-sizm, and yet which is effective, powerful, simple, relatively economical, and lacking in structural complexity.

While I have shown my invention in only one form, it will be obvious to those skilled in the art that it is not so limited, but is susceptible of various changes and -modifications without departing from the spirit thereof.

1 claim:

'1. A press comprising, a bed; a plurality of driveunits, each said drive unit comprising a housing containing a plurality'of gear systems each'driven byan electricmotor and having an output pinion, each said housing being fixed relative to said bed and being disposed with its longitudinal axis perpendicular to the longitudinal axisof said bed and having a portion extending outwardly over said bed; a movable element adapted for cooperation with said bed; aplurality of spaced parallel racks fixed to the upper side of said movable element and perpendicular thereto; a guideway carried by each said housing 'at the front'side thereof extending over said bed, each said lguideway adapted for receiving one of said racks for guided reciprocating movement therein, with each said rack engaged by output pinions of the gear systems of a'respective drive unit; and means mechanically interconnecting the gearing of each said gear system of one said drive unit with the corresponding gear system of the adjacent "drive unit ahead ofthe respective gear system output pinion, whereby all'said gearing systems will be synchronized and said interconnecting means in each case shall carry only the differential torque load imposed by adjacent gear systems to effect distribution of the total load among said electric motors.

2. A press-comprising, a bed; a plurality-of drive units, each said drive unit comprising a housing containing a plurality of gear systems each driven 'by 'an electric motor and having an output pinion, each saidhousing-being fixed relative to said bed and being disposed with its longitudinal axis perpendicular'to the longitudinal axis ofsa'id bed and having a'portion extending outwardly over said bed; a movable element adaptedfor cooperation with said bed; a plurality of spaced parallel rams fixed to the upper side of said movable element and perpendicular thereto, each said ram comprising a'guide member anda rack fixed relative to said guide member; a guidewaycan ried by-each said-housing atthe-front-side'thereof extend ing over said =bed, each said guideway mounting rollers adapted for receiving said rack guide therebetween for guided reciprocating movement therein, with each said rack engaged by output pinions of the gear systems of a respective drive unit; and means mechanically interconnecting the gearing of each said gear system of one said drive unit with the corresponding gear system of the adjacent drive unit ahead of the respective gear system output pinion, whereby all said gearing systems will be synchronized and said interconnecting means in each case shall carry only the difierential torque load imposed by adjacent gear systems to efiect distribution of the total load among said electric motors.

3. A metal forming press comprising, a bed adapted for carrying a first die element; a pair of upstanding drive units spaced apart symmetrically disposed adjacent one side of said bed and fixed relative to said bed, with each said drive unit having portions extending outwardly over said bed, each said drive unit comprising a plurality of gear systems, each driven by an electric motor and having an output pinion, and a guideway; a movable element adapted for carrying a second die element complementing said first die element; a pair of spaced parallel racks fixed to said movable element and perpendicular thereto, each said rack being carried in a respective drive unit guideway and engaged by output pinions of respective gear systems; and means mechanically interconnecting the gearing of each said gear system of one said drive unit with the corresponding gear system of the adjacent drive unit ahead of the respective gear system output pinion, whereby all said gearing systems will be synchronized and said interconnecting means in each case shall carry only the differential torque load imposed by adjacent gear systems to effect distribution of the total load among said electric motors.

4. A press comprising, a bed; a plurality of drive units having portions extending outwardly over said bed and fixed relative to said bed, each said drive unit comprising a plurality of gear systems each driven by an electric motor and having an output pinion, and a guideway; a movable element adapted for cooperation with said bed; a plurality of spaced parallel racks fixed to said movable element and perpendicular thereto, each said rack being carried in a respective drive unit guideway and engaged by output pinions of respective gear systems, means mechanically interconnecting the gearing of each said gear system of one said drive unit with the corresponding gear system of the adjacent drive unit, ahead of the respective gear system output pinion whereby all said gearing systems will be synchronized and said interconnecting means in each case shall carry only the differential torque load imposed by adjacent gear systems to efiect distribution of the total load among said electric motors.

References Cited in the file of this patent UNITED STATES PATENTS 357,160 Toepfer Feb. 1, 1887 741,718 Roberts Oct. 20, 1903 914,336 Damron Mar. 2, 1909 1,093,378 Bogen Apr. 14, 1914 1,387,509 Nottage Aug. 16, 1921 1,469,689 Prius Oct. 2, 1923 1,694,585 Dreis Dec. 11, 1928 1,975,249 Bradley Oct. 2, 1934 FOREIGN PATENTS 529,876 France Sept. 19, 1921 399,364 Germany July 29, 1924; 

